Bobbin holder

ABSTRACT

A bobbin holder for receiving and securing a conical or cylindrical tube is provided with a support tube, a conical clamping ring axially movably mounted on the support tube, and a pair of spreading levers each having a free end and being pivoted for movement toward or away from each other in a plane which includes the axis of the support tube. The clamping ring and the spreading levers are spaced from each other in the axial direction of the support tube. The pivots of the levers are closer than the free ends of the levers to the clamping ring. The position of the clamping ring closest to the pivots of the spreading levers is the smallest diameter portion. The clamping ring and the spreading levers are, accordingly, adapted to engage the respective ends of the conical or cylindrical tube and thus secure the conical or cylindrical tube.

llnited States Patent Raasch et a1.

BOBBIN HOLDER Inventors: Hans Raasch, Rheydt; Dietmar Engelhardt; Wilhelm Maassen, Monchengladbach, all of Germany W. Schlafhorst & Co., Monchengladbach, Germany Filed: May 18, 1973 Appl. No.: 361,461

Assignee:

Foreign Application Priority Data May 26, 1972 Germany 2225556 References Cited UNITED STATES PATENTS 6/1954 Huber 242/129] 7/1967 Noquera 242/130 IIIIIIIIIIII III/I 3,400,899 9/1968 Tytgath 242/130 Primary Examiner-Leonard D. Christian Attorney, Agent, or Firm-Herbert L. Lerner 57 ABSTRACT A bobbin holder for receiving and securing a conical or cylindrical tube is provided with a support tube, a conical clamping ring axially movably mounted on the support tube, and a pair of spreading levers each having a free end and being pivoted for movement toward or away from each other in a plane which includes the axis of the support tube. The clamping ring and the spreading levers are spaced from each other in the axial direction of the support tube. The pivots of the levers are closer than the free ends of the levers to the clamping ring. The position of the clamping ring closest to the pivots of the spreading levers is the smallest diameter portion. The clamping ring and the spreading levers are, accordingly, adapted to engage the respective ends of the conical or cylindrical tube and thus secure the conical or cylindrical tube.

10 Claims, 9 Drawing Figures I/IIIII/I SHEET 1 OF 3 l v F 5 m PATENTL E31 2 6 E974 SHEEI 2 OF 3 FIGA FIGS "1111111, 'IIIIIIIIIIIIIIIIIII/ .90

BOBBIN HOLDER The invention relates to a bobbin holder for receiving and securing conical and cylindrical tubes, the bobbin holder comprising movable or resilient elements which are provided with contoured contact surfaces for the tube ends.

If threads are to be drawn at high speed from yarn bobbins wound on conical or cylindrical tubes, it is necessary to provide a firm mounting for the tubes. A tube mounting should furthermore ensure that the central axis of a yarn bobbin is always aligned toward the center of the inlet eyes or the like that are disposed in the path of the thread. In automatic winding machines the spool of yarn to be unwound is usually swung automatically from a standby position into the unwind position. It can furthermore happen that the yarn bobbin is subject to a movement during the unwinding process. A tube must therefore be secured so that it cannot be loosened from its seat either by the weight of the spool of yarn or by the gravitationally produced forces that occur. As already mentioned, there are tubes of conical and cylindrical shape. Besides the shape, however, the diameter and the length of such tubes may also vary over wide ranges.

A bobbin holder should be suited for as many types of tubes as possible without the necessity to change parts of the bobbin holder or to perform timeconsuming adjustments. Finally, it should be possible to remove empty tubes easily and to push full bobbins onto the bobbin holder without effort.

These diverse requirements have been met only partially by the bobbin holders of the prior art.

It is an object of the invention to create a bobbin holder for receiving the most varied tubes, in which the shortcomings described above are avoided and which holds the yarn bobbins to be unwound with sufficient reliability and centering accuracy in the most varied types of textile machines in stationary position as well as under continuous change of position.

According to the invention, this problem is solved by the provision that the bobbin holder comprises a support tube which is equipped with a clamping ring that is adjustable according to the length of the tube and forms the contact surface for one end of the tube, and with two spreading levers that are adjustable according to the diameter of the tube and form the contact surface for the other end of the tube. The conical clamping ring assures good Contact and centering of tubes of small and large diameters, regardless of whether the tube is of conical or cylindrical shape. The two spreading levers adapt themselves likewise to any tube diameter, forming a further contact surface. In this manner, positive support on both sides is achieved for the pushed-on tubes with their yarn bodies.

The great adaptability of the bobbin holder according to the invention is obtained by the fact that the spreading levers are fulcrumed at the support tube and are enclosed in the region of the fulcrums by a circular spring element. It is particularly advantageous here that the spreading levers be provided with sloping guide surfaces.

For adjusting the spreading levers to different centering diameters. it is of advantage, according to a further feature of the invention, that a push rod which is provided with a transverse pin and adjusts the spreading levers through their guide slopes, be arranged in the support tube.

tan a ,u and tan (oz/2) p.

For in that case it is assured that with uniformly distributed pressure, such as is produced when a tube is pushed on, the spreading levers can be pushed together easily. If, however, forces act unevenly on the spreading levers from the outside, for instance, static and/or dynamic forces due to the weight of the bobbins, these forces are always counteracted by forces which cause self-locking between the individual parts and thereby ensure, nevertheless, a secure holding of the tube with its body of yarn.

In the case that axial forces are exerted on the spreading levers, such as are produced, for instance, if the bobbins hang vertically, the same advantages can be obtained if, in addition to the conditions stated above, the spreading angle [3 of the spreading levers and the friction coefficient p. are matched in such a manner that the following relation is fulfilled:

tan/3 p.

In order to facilitate the removal of an empty tube, the push rod can be coupled with a switching lever. This switching lever can be operated manually as well as automatically. Automatic operation is possible, for instance, during the swinging motion of the bobbin holder from an unwind position into a stand-by or loading position. The removal of an empty tube can further be facilitated by providing that the push rod be coupled by slide wires for bridging the contact surfaces of the spreading levers. In this manner the inner edge of an empty tube is prevented from catching upon removal of the empty tube.

In order to facilitate the adjustment of the conical clamping ring on the support tube and the setting of the transverse pin of the push rod in the event that different tube sizes and shapes must be accommodated frequently, it is also advantageous to provide the support tube and the spreading levers with scale markings.

The invention will now be described in greater detail by reference to a specific embodiment illustrated in the drawings, in which:

FIG. 1 is a longitudinal cross section through the bobbin holder with a spool of yarn in the clamped condition;

FIG. 2 is a fragmentary longitudinal cross section through the bobbin holder and spool of FIG. 1 in a plane perpendicular to FIG. 1;

FIG. 3 is a front view for FIG. 2;

FIG. 4 is the bobbin holder in the view according to FIG. 1 being manually operated to release the tube;

FIG. 5 is a view corresponding to FIG. 1 but with a short, cylindrical tube and corresponding bobbin body now being clamped on the bobbin holder and a cam being provided for mechanical operation of the push rod;

FIG. 6 is a view which illustrates the forces on the substantially horizontal bobbin holder under various possible loads;

FIG. 7 is a force diagram of the forces in FIG. 6;

FIG. 8 is a view which illustrates the forces on a bobbin holder arranged in a substantially vertically downwardly hanging position; and

FIG. 9 is a view which illustrates the forces on the bobbin holder when a tube is pushed on.

As may be seen from FIG. 1, the bobbin holder 1 consists of a support sleeve or tube 2, which in the embodiment shown here is screwed to an unwind frame 3. At the end opposite the screw connection, the support tube 2 has two pins 4, which can be seen particularly clearly in FIG. 2. The two spreading levers 5 and 6 are pivoted on the pins 4. The sliding sleeve 7, which is provided with an internal thread, is movably supported in the support tube 2. A push rod 8 is screwed into the sliding sleeve 7. The push rod 8 is firmly connected to a transverse pin 9, which may be seen particularly clearly in FIG. 3. The two guide slopes 5' and 6' of the spreading levers 5 and 6 bear against the transverse pin 9. In the vicinity of the respective fulcrum of each, the two spreading levers 5 and 6 have a slot-like recess, into which a circular spring element 10 is placed. The circular spring element 10 pushes the spreading levers 5 and 6 against the transverse pin 9. A sleeve 11 is firmly connected to the slide bushing 7. At its end remote from the slide bushing 7, the sleeve 11 has two bearings 12 into which the slide wires 13 are received. The slide wires 13 are designed so that they disappear within the contour of the spreading levers 5 and 6 in the position shown in FIG. 1. The point of exit of the slide wires 13 in the spreading levers is situated at the point where a groove forms the contact surface 14, against which the front end of the conical tube 15 can brace itself. In FIG. 1 the conical tube 15 carries a yarn body 16. The sliding bushing 7 is pinned to the shaft 17, which in turn carries the collar 18 which is secured axially on the shaft 17 by the retaining ring 19. A washer 20 bears against a step in the support tube 2. A compression spring 21 pushes the collar 18 and the washer 20 against the step in the support tube 2 and the retaining ring 19, respectively. It will be seen that through the retaining ring 19, which is inserted into a groove in the support tube 2, a positive fixation of the shaft 17 and thereby also of the slide bushing 7 is effected. A switching lever 22 is fulcrumed at the bearing 23 and connected to the shaft 17 by a pin 24. By moving the switching lever 22 counterclockwise (FIG. 4) the shaft 17 can be moved against the force of the compression spring 21.

The conical clamping ring 25 is movably attached to the support tube 2 by means of a cup spring 27 which rests with its outer diameter against a counterbore in the conical clamping ring 25 and can be clamped or released by the clamping disc 28. As the forces due to the weight of the yarn body 16 or the gravitationally produced forces which act on the conical clamping ring 25 tend to move the latter to the right, the inclined position of the cup spring 27 counteracts these forces, so that the clamping disc 28 needs to be pulled up only to the extent that the cup spring 27 barely just grips the support tube 2.

The operation of the bobbin holder 1 is as follows. When a yarn body 16 has run out. the empty tube 15 must be removed and replaced by a full bobbin on a tube. For this purpose, the switching lever 22 is gripped with one hand and is swung counterclockwise as shown in FIG. 4. In FIG. 5 the bobbin holder 1 is provided with a switching lever 22' which can also be operated mechanically, for instance, by means of a cam 29. By swinging the switching leber 22 or 22', respectively, counterclockwise, as shown in FIG. 4, the shaft 17 and thereby also the slide bushing 7 are removed to the left. At the same time the push rod 8, which is screwed into the slide bushing 7, is also shifted, so that the guide surface slopes 5' and 6 slide along the transverse pin 9 to reduce the spreading angle of the two spreading levers 5 and 6. This process is aided by the circular spring element 10. With the slide bushing 7, the sleeve 11 with its bearing 12 and the slide wires 13 have also shifted to the left. Thereby, the slide wires 13 project from the spreading levers 5 and 6 and cover up the contact surfaces 14. Now the empty tube 15 can he slid off without resistance. When the empty tube 15 has been slid off, the switching lever is released and the parts of the bobbin holder 1 resume the positions shown in FIG. 1.

Because of the great weight of the yarn spools to be processed, the operator always will want to grasp a full bobbin with both hands to place it on the bobbin holder 1, so in that case the switching lever 22 cannot also be operated by the operator. However, this is not necessary, as a tube 15 pushed over the released spreading levers 5, 6 pushes the latter together because of the smaller diameter of the tube 15. This produces an axial force against the action of the compression spring 21, which with proper design of the guide surface slopes 5, 6 on the spreading levers 5, 6 causes an axial shift of the push rod 8 with the transversal pin 9 to the left. Thereby, the mutual spacing of the spreading levers 5, 6 is reduced, and the Wound tube 15 can be pushed on up to the conical clamping ring 25. When the tube 15 is pushed on so far that the contact surfaces 14 are exposed again, the spreading levers 5, 6 will spread apart so far that the tube 15 now makes positive contact reliably also at this end.

In FIG. 5 is illustrated how the bobbin holder 1 is adapted to another tube configuration. While in FIG. 1 an elongated conical tube 15 is mounted, in FIG. 5 a shorter cylindrical tube 29 is mounted. For switching to the other tube format, the spreading levers 5 and 6 are swung apart so far that the transverse pin 9 can be turned freely. The push rod 8 is subsequently screwed into the slide bushing 7 so far that the spread of the spreading levers 5 and 6 corresponds to the hole of the tube when the guide slopes 5' and 6' rest against the transverse pin 9. After the hold of the cup spring 27 is released by releasing the clamping disc 28, the conical clamping ring 25 is moved until the tube 29 is held axially and radially between the contact surfaces 14 of the spreading levers 5, 6 and the clamping ring 25. Then the clamping disc 28 is pulled up again. Securing the push rod 8 against rotation is not necessary, as the spreading levers 5, 6 are pushed against the transverse pin 9 by the circular spring element 10 and prevent rotation in this manner. The indicator markings 30 and 31 applied respectively on the support tube 2 and the guide slopes 5', 6 can facilitate the adjustment when going from one tube configuration to another.

As heretofore mentioned, a particular advantage of the bobbin holder 1 according to the invention resides in the fact that in the case of forces acting unevenly from the outside on the spreading levers 5, 6, selflocking is caused between certain parts and the holding of the tubes is reliably assured. On the other hand, the spreading levers 5, 6 can easily be pressed together if the pressure is distributed on the spreading levers 5, 6 uniformly, such as is the case if a new bobbin of yarn is pushed on. For this operation, the self-locking of the longitudinally moving parts is inoperative.

It will be seen from FIG. 6 and the force diagram of FIG. 7 that a force P acting unilaterally on the spreading lever 6 produces a contact force P, at the transverse pin 9. P deviates from the vertical by the contact angle a. The inclined contact force P acts upon the push rod 8 as the axial component A and the radial component P Axial component A acts on the push rod 8 in the release sense. Resisting movement of the transverse pin 9 along the guide slope 6' is a friction force P 'p. produced at the point of contact. This friction force is perpendicular to P and acts upon the push rod 8 as the axial component A and the radial component P A counteracts A. The radial components P and P act on the push rod 8 as lever forces and produce the support reaction forces P and P at the support points of the push rod 8. Resisting movement of the push rod 8 axially due to the force A, the support friction force P u and P ,u. is produced at the support points of the push rod 8. These friction forces are perpendicular to P and P and act against the axial force A. Finally, also the bias force A of the compression spring 21 acts against the axial force A. The spreading lever 6 cannot be released by the force P if the condition A P u P p. A 2 A is fulfilled. One can thereby determine the limit conditions, for which a bobbin holder according to the invention is still self-locking under the action ofa unilateral force P. If one assumes that the friction coefficient p. at the contact surface between the transverse pin 9 and the guide slopes 5 and 6' as well as at the support surfaces is the same, the contact angle 04 can be given as a function ofthe friction coefficient [.L. if the spreading levers 5, 6 are of steel and the bobbin is wound on a plastic tube, resulting in a friction coefficient ]J. 0.3, and the condition tan (ct/2) ,u. is fulfilled, a contact angle a 33.5 still gives reliable self-locking.

Another case of loading is obtained if the bobbin holder 1 is arranged, for instance, hanging vertically, as indicated in FIG. 8. If the spreading levers 5 and 6 are designed so that their contact surfaces 14 are on a radius R the pivot point of which coincides with the center of the pins 4, 4' and if the angle by which a spreading lever 5 was swung from the vertical in order to hold a tube is designated as B, the following conditions are obtained for axial loading:

The axial load acts, for instance, through the cylindrical tube 29, in equal parts on the spreading levers 5 and 6 as P One can consider P, as divided into a force P perpendicular to the contact surfaces l4 and the component P generated at an angle of 90 thereto. The component P produces an axial force A on the push rod 8, which would have a releasing effect. As an oppositely directed force P is generated by the spreading levers 5, 6, the support forces such as are generated in the case of a unilateralapplication of force, do not become effective. Thus, the friction forces counteracting the axial force A are also eliminated. However, the friction forces P a, which become effective at the contact surfaces 14, additionally oppose the collapsing of the spreading levers 5, 6. P a is effective at the same angle but in opposite direction as P If one wants to cancel the effect of P then P p. must be equal to or greater than P Therefrom. the limit condition for self-locking with an axial load is obtained tan ,B E a. This condition indicates how large the spreading angle ,8 can be allowed to become for a given friction coefficient between the tube and the spreading lever.

For a friction coefficient p. 0.3, for instance, one obtains 16.7 for this.

If a tube with a body of yarn is to be pushed on without operating the switching layer 22, the following conditions must be considered:

As may be seen from FIG. 9, a force P and P inclined against the vertical by an angle (1 acts on the transverse pin 9 if a tube is pushed on. These forces act on the push rod 8 as equidirectional axial forces A and A,,, while the radial components P and P have opposing directions and mutually cancel. At the contact surface of the transverse pin 9 and the guide slopes 5', 6', friction forces P a and P ,u. are generated during the movement. Also in this case, the radial components on the push rod 8 are ineffective, as they are of opposite direction. The axial components A and A are opposed here to the axial forces A, and A If the push rod 8 is to move axially due to uniform pressure on the spreading levers 5, 6, the condition A A A A must be fulfilled. This gives the limit condition, at which no self-locking occurs while a tube is pushed on. The range of the contact angle a is defined by the following relation:

tana p.

Within a range, which for a friction coefficient a of 0.3 is between 16.7 and 335, a mean value for the contact angle a can be selected which offers even for deviations of the assumed friction coefficient sufficient safety that the desired conditions are achieved.

We claim:

1. Bobbin holder for receiving and securing a conical or cylindrical tube, comprising a support sleeve having an axis, a conical clamping ring axially movably mounted on said support sleeve, a pair of spreading levers each having a free end, pivot means for pivoting said levers toward or away from each other in a plane which includes the axis of said support sleeve, said clamping ring and said spreading levers being spaced from each other in axial direction of said support sleeve, said pivot means being closer than said free ends of said levers to said clamping ring, said clamping ring having a portion thereof of minimum diameter facing toward said pivot means, said clamping ring and said pair of spreading levers thereby being adapted to engage respective ends of the tube and thus secure the tube on the bobbin holder.

2. Bobbin holder according to claim 1, in which said pivot means are located on said support sleeve, and including a circular spring encircling said spreading levers in the vicinity of said pivot means.

3. Bobbin holder according to claim 1, in which said spreading levers are provided with mutually facing guide surfaces, and including a pin arranged in engagement with said guide surfaces, said pin having an axis disposed transversely to said axis of said support sleeve.

4. Bobbin holder according to claim 3, including a push rod axially movably mounted coaxially in said support sleeve, said pin being mounted on said push rod, whereby axial movement of said push rod moves said pin along said guide surfaces of said spreading levers and thereby adjusts said spreading levers.

5. Bobbin holder according to claim 4, in which each of said guide surfaces is shaped so that an angle a is defined between said guide surface at any point at which said guide surface is to contact the pin in operation of the bobbin holder and the axis of the push rod is such that tan a p. and tan (a/2) ,u, wherein [.L is the ocefficient of friction between the material of said spreading levers and the material of the tube.

6. Bobbin holder according to claim 1, in which a spreading angle ,8 of each of the spreading levers, which is the angle between the axis of said support tube and a line from the pivot means of said spreading levers to the point on said spreading lever which contacts an end of the tube, and the coefficient of friction ,u. between the material of said spreading lever and the material of the tube are such that tan B pt.

7. Bobbin holder according to claim 4, further comprising lever means coupled to said push rod for axially moving said push rod.

8. Bobbin holder according to claim 4, in which a groove is formed in each of said spreading levers to define a surface which is adapted to contact an end of the tube when the latter is secured on the bobbin holder,

and further comprising a pair of slide wires coupled to said push rod, each of said slide wires being positioned to be received in the groove of a respective one of said spreading levers and thereby cover said contact surface when said push rod is actuated to release the tube secured on the bobbin holder.

9. Bobbin holder according to claim 3 in which the guide surfaces of said spreading levers are provided with indicator markings to assist in adjusting the spread of said spreading levers, and said support tube has an external surface provided with indicator markings to assist in adjusting the axial position of said clamping ring on the tube.

10. Bobbin holder for receiving and securing a conical or cylindrical tube, comprising a support sleeve, and a pair of means having respective contoured surfaces engageable with the ends of a tube, disposed around said support sleeve, one of said means comprising a substantially conical clamping ring mounted on said support sleeve and movable along the length thereof into engagement with one of the ends of the tube, and the other of said means comprising a pair of spreading lever means respectively fixed at one end thereof relative to said support sleeve and yieldably adjustable at the other end thereof to the diameter of the tube and engageable with the other end of the tube. 

1. Bobbin holder for receiving and securing a conical or cylindrical tube, comprising a support sleeve having an axis, a conical clamping ring axially movably mounted on said support sleeve, a pair of spreading levers each having a free end, pivot means for pivoting said levers toward or away from each other in a plane which includes the axis of said support sleeve, said clamping ring and said spreading levers being spaced from each other in axial direction of said support sleeve, said pivot means being closer than said free ends of said levers to said clamping ring, said clamping ring having a portion thereof of minimum diameter facing toward said pivot means, said clamping ring and said pair of spreading levers thereby being adapted to engage respective ends of the tube and thus secure the tube on the bobbin holder.
 2. Bobbin holder according to claim 1, in which said pivot means are located on said support sleeve, and including a circular spring encircling said spreading levers in the vicinity of said pivot means.
 3. Bobbin holder according to claim 1, in which said spreading levers are provided with mutually facing guide surfaces, and including a pin arranged in engagement with said guide surfaces, said pin having an axis disposed transversely to said axis of said support sleeve.
 4. Bobbin holder according to claim 3, including a push rod axially movably mounted coaxially in said support sleeve, said pin being mounted on said push rod, whereby axial movement of said push rod moves said pin along said guide surfaces of said spreading levers and thereby adjusts said spreading levers.
 5. Bobbin holder according to claim 4, in which each of said guide surfaces is shaped so that an angle Alpha is defined between said guide surface at any point at which said guide surface is to contact the pin in operation of the bobbin holder and the axis of the push rod is such that tan Alpha > Mu and tan ( Alpha /2) < Mu , wherein Mu is the ocefficient of friction between the material of said spreading levers and the material of the tube.
 6. Bobbin holder according to claim 1, in which a spreading angle Beta of each of the spreading levers, which is the angle between the axis of said support tube and a line from the pivot means of said spreading levers to the point on said spreading lever which contacts an end of the tube, and the coefficient of friction Mu between the material of said spreading lever and the material of the tube are such that tan Beta < or = Mu .
 7. Bobbin holder according to claim 4, further comprising lever means coupled to said push rod for axially moving said push rod.
 8. Bobbin holder according to claim 4, in which a groove is formed in each of said spreading levers to define a surface Which is adapted to contact an end of the tube when the latter is secured on the bobbin holder, and further comprising a pair of slide wires coupled to said push rod, each of said slide wires being positioned to be received in the groove of a respective one of said spreading levers and thereby cover said contact surface when said push rod is actuated to release the tube secured on the bobbin holder.
 9. Bobbin holder according to claim 3 in which the guide surfaces of said spreading levers are provided with indicator markings to assist in adjusting the spread of said spreading levers, and said support tube has an external surface provided with indicator markings to assist in adjusting the axial position of said clamping ring on the tube.
 10. Bobbin holder for receiving and securing a conical or cylindrical tube, comprising a support sleeve, and a pair of means having respective contoured surfaces engageable with the ends of a tube, disposed around said support sleeve, one of said means comprising a substantially conical clamping ring mounted on said support sleeve and movable along the length thereof into engagement with one of the ends of the tube, and the other of said means comprising a pair of spreading lever means respectively fixed at one end thereof relative to said support sleeve and yieldably adjustable at the other end thereof to the diameter of the tube and engageable with the other end of the tube. 